Pollution Cancer Risk Down 15% In Southern California, But Still Too High

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Article Date: 05 Jan 2008 - 10:00 PDT

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If you live in Southern California, your risk of developing cancer as a result of air pollution is 15% lower today than it was about 10 years ago, according to a two year study carried out by the South Coast Air Quality Management District. Barry Wallerstein, Executive Officer, South Coast Air Quality Management District (South Coast AQMD), said that while there have been some improvements; the remaining risk level is way too high.

It is now estimated that approximately 1,200 in every 1,000,000 people in Southern California who lives for 70 years will develop cancer as a result of air pollution. If the area is estimated to have over 20 million people, that is a lot of cancers. If you live near the ports of Los Angeles and Long Beach, where diesel emissions are high, your risk of such cancers may be as high as 2,900 per million.

Diesel emissions are the main cause of cancers caused by air pollution in the area, making up 84% of the risk, according to the study.

William Burke, Chairman of the South Coast AQMD Governing Board, said ".. the remaining cancer risk is completely unacceptable. Thousands of residents are getting sick and dying from toxic air pollution. Some of them live in low-income, minority neighborhoods that may be heavily impacted by cancer-causing air pollution."

The two LA ports are responsible for over 40% of all containerized cargo that comes into the United States annually. These ports have grown rapidly, and with that has come an increasing in traffic from trucks, vehicles in general, and ships. There are plans, say officials, to cut this particular air pollution by four-fifths over the next few years.

Anaheim has the lowest air pollution cancer risk in the area, while downtown LA, Fontana, Huntington Park, Wilmington and Burbank have the highest.

The Study (Called MATES III)

Samples were taken once every three days, from 10 fixed sites. This occurred for one full year at all ten sites and for two years at eight sites.

Major findings

-- Air pollution cancer risk overall for the area was 1,200 per million.

-- Diesel exhaust accounted for 84% of air toxic risk.

-- Of the pollutants measured, only formaldehyde was above the current chronic exposure levels developed by OEHHA (Office of Environmental Health Hazard Assessment). However, OEHHA has proposed revised limits. If the proposed limits are approved, the only measured pollutant that would exceed the OEHHA limits would be manganese.

-- Most substances gave lower readings compared to the previous 1999 MATES II study.

-- There was a drop of 50% in Benzene and 73% in 1.3-butadiene levels compared to 1999. These pollutants mainly come from vehicle exhausts.

-- There was a drop of 53% in methylene chloride (solvent used in paint remover) and 78% in perchloreothylene (industrial solvent used in dry cleaning) levels compared to the previous MATES II study.

-- Levels of elemental carbon in the PM10 particulate fraction were approximately 38% lower than those found in MATES II. About a 10% reduction was traced to a difference in analytical instrumentation used in MATES III. The net 28% reduction in ambient levels may reflect decreased emissions combined with annual meteorological differences.

-- Estimated cancer risk during the second year of this latest study was higher than during the first year. As the first year had significantly more rainfall, the levels of particulate matter in the air during this first year would have been lower.

-- Modeling analysis also showed higher levels of air pollution along freeways and near intermodal facilities.

Click here to view the PDF files of the MATES III study

Written by - Christian Nordqvist
Copyright: Medical News Today
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